Long-Term Pollutant Exposure Tied to Uncontrolled Asthma

Exposure to PM10 and O3 affects three main domains of asthma control

FRIDAY, June 24 (HealthDay News) - Long-term exposure to particulate matter smaller than 10 µm (PM10) and ozone (O3) is associated with uncontrolled asthma in adults, according to a study published online June 20 in the Journal of Epidemiology & Community Health.

Bénédicte Jacquemin, M.D., from the CESP Centre for Research in Epidemiology and Population Health in Villejuif, France, and colleagues investigated the associations between long-term exposure to nitrogen dioxide (NO2), O3, and PM10 and asthma control in 481 participants with asthma. Using the 4 km grid air pollutant surface model, outdoor concentrations of O3, NO2, and PM10 were estimated for residential addresses. Asthma control was assessed based on the 2006 to 2009 Global Initiative for Asthma guidelines. The association between air pollution and the three domains of asthma control -- symptoms, exacerbations, and lung function -- was evaluated.

The investigators found that the median concentrations measured in micrograms per cubic meter were 32 for NO2 in 465 participants, and 46 for O3, and 21 for PM 10 in 481 participants. Asthma was controlled in 44 percent, partly controlled in 29 percent, and uncontrolled in 27 percent of the participants. The unadjusted ORs for O3 and PM10 were 1.69 and 1.35, respectively, with asthma control, and the associations persisted when both pollutants were included in the model. Adjustment for confounding variables did not modify the associations. Both O3 and PM10 were associated with the three main domains of control.

"The results suggest that long-term exposure to PM10 and O3 is associated with uncontrolled asthma in adults, defined by symptoms, exacerbations, and lung function," the authors write.

The Epidemiological study on the Genetics and Environment of Asthma was partially funded by grants from Merck Sharp & Dohme.